Find the next number in the sequence

5 12 24 36 ?

You are confined in a room and given two metal rods. Out of these two rods, one is magnet and the other is the iron rod. They look starkly similar. You don't have any other metal object in the room.

How will you decide which one of those is magnet?

Replace the question mark with the correct number in below Picture:

What is the next number in the series?

15 29 56 108 208 ?

What always comes into a house through the keyhole?

What month of the year has 28 days?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

I got a bee but no honey.
got an eye but am still blind.
got a sea but no water.
got a tea but no coffee.
got a why but no answer.

What Am I?

Who always enjoys poor health?

Can you solve below mathematical equation?

2^1234 - 2^1233